1. Field of the Invention
The invention relates to a chair. More particularly, this invention relates to a pump assembly for use with a chair having a chair back equipped with an expandable fluid bladder for lumbar support.
2. Description of the Related Art
In the workplace, persons such as machine operators and secretaries are often required to perform tasks in a sedentary position. Without proper support of the back, the person can become fatigued and possibly subjected to back strain. It is now known that utilizing ergonomic principles in chair design can increase a worker's productivity, reduce back fatigue, and reduce the likelihood of the incidences of back strain.
One area in which this proper support is especially necessary is the support of the lumbar or lower region of a seated person's back. It is known in the chair design industry that it is possible to provide a solid cushion in the lumbar region of the back of the chair for back support. Typically, these cushions are made of foam material. However, it has been found that such a foam cushion proves uncomfortable to the user over time.
It is also known in the chair design industry to provide lumbar support into the back of a chair in another way: by using an expandable fluid bladder. Expandable fluid bladders have proven to be more comfortable than foam cushions. One type of expandable fluid bladder--an air bladder--is described, for example, in U.S. Pat. No. 5,758,925 to Schrewe, et al. and in U.S. Pat. No. 4,518,200 to Armstrong.
Recently, chairs have been designed incorporating these expandable fluid bladders directly into the back of chairs. Pump means in the form of rubber bulb pumps have been incorporated into chair backs to inflate the expandable fluid bladders. Some of these chair backs have the pump means hidden behind a foam cushion; some of these chair backs have a rubber bulb pump protruding from the back of the chair back. In either event, a person sitting the in the chair cannot easily inflate the lumbar support while seated in these chairs. This is problematic since a person should be seated to properly determine whether the inflation level of the expandable fluid bladder is adequate to support the back. With these chairs the person must get out of the chair, then inflate the expandable fluid bladder, and then return to the seat to test the lumbar support. Accordingly, these prior chairs are inconvenient because much time is wasted in adjusting the lumbar support.
It is also known in the chair design industry that expandable fluid bladders must be deflatable as well as inflatable in order to be practical. To that end, conventional chair backs with air bladders are provided with a fluid release or button located somewhere on the chair. By depressing this fluid release or button, the air bladder is deflated.
However, in these prior chairs, one tool is used to inflate the expandable fluid bladder and a different mechanism is used to deflate the expandable fluid bladder. For instance, the rubber bulb pump may be used to inflate the air bladder, while the fluid release or button is used to deflate the air bladder. Because at least two different mechanisms are manipulated to adjust the air bladder, a user cannot conveniently adjust the air bladder from a seated position to attain proper lumbar support.
Portable cushions with air bladders for lumbar support are also well-known as discussed in U.S. Pat. No. 4,518,200 to Armstrong. However, these portable supports are not practical for use in the modem workplace where durable furniture is preferred.
For the foregoing reasons, there is a need for a pump assembly that can overcome, or at least minimize, one or more problems set forth above.